The hydraulic pressure prevalent in a water supply network is an important quality feature. A high pressure guarantees that a large amount of water can be taken from the supply network within a short period of time for industrial bulk consumers and fire hydrants. At the house connections, a sufficiently high water pressure allows whole buildings, right up to the top level, to be reliably supplied with drinking water without additional pump apparatuses.
On the other hand, excessively high pressure in the supply network leads to premature aging and failure of components, for example by pipes breaking. The leaks caused thereby lead to high repair costs, water losses and, in some cases, to further damage of surrounding structures. Moreover, excessive pressure leads to an increased water loss as a result of background leaks. Such background leaks are present in every water network to a certain extent and have as a consequence a continuous loss of drinking water. Moreover, an excessive flow pressure increases the frictional losses occurring in the case of pipe flows. In supply networks in which the pressure is built up by pumps, an increase in the provided pressure immediately leads to an increased energy requirement of the pumps.
Operators of supply networks are therefore presented with the challenge of finding a compromise between these two opposing requirements in respect of the hydraulic pressure provided in the supply network. This decision is additionally made more difficult by virtue of the pressure prevalent during operation being strongly influenced by the consumption load, which may be exposed to large variations and often cannot be reliably measured or predicted. These consumption variations and switching processes of pumps and valves can furthermore lead to transient pressure peaks in the supply network, which can have a damaging effect on network components and often constitute the cause of suddenly occurring leaks.
These days, a continuously high pressure is provided in a targeted manner in many water supply networks by way of elevated tanks or continuously operating pumps. The design of the network components is already deliberately over-scaled during planning. The excessive pressure in the supply network is reduced at the points of consumption by pressure reduction apparatuses to a measure which is expedient for the consumers. The disadvantages, listed above, as a result of the long-term operation at a high pressure are often accepted.
Approaches in respect of adapting the pressure prevalent in the water distribution network to the requirements of the consumers in a targeted manner and, as a result thereof, in respect of avoiding excessive pressures together with the disadvantages accompanying these were only developed in the relatively recent past under the byword of pressure management [TL]. The techniques developed in the process include the subdivision of the supply network into pressure management zones (PMZ), in which the pressure is reduced to a minimum at the inflows as a result of targeted control of valves or pumps. Here, knowledge about the network structure, the topographic conditions of the pressure management zone and about number and type of the connected consumers is used for designing the pressure control. In order to be able to react to the dynamic pressure variations caused by changing consumption, pressure values in the zone measured online have also been adopted in the meantime for the pressure control [UBRR].